1. Field of the Invention
This invention relates to a programmable mask for exposure apparatus and, more particularly to a pattern exposure mask which is formed by an integrated pixels of a micro-devices which shut or open a light by an electrical signal.
2. Description of the Related Art
There are several different kind of methods for pattering a micro pattern such as semiconductor integrated circuits on a semiconductor wafer such as an e-beam lithography method drawing the patterns directly by injecting an electron beam on the semiconductor wafer coated with a photoresist and a projection method, an indirect method, projecting the patterns printed by 5 or 10 times bigger than a real size on a mask by using an exposure apparatus projecting the patterns repeatedly by reducing the size optically to 1/5 or 1/10 of the original pattern size on the semiconductor wafer coated with photoresist.
Generally, the projection method needs many masks for fabricating a semiconductor devices and the mask is fabricated by printing a circuit pattern with a metal film such as a chromium so that it blockade light on a projection quartz substrate.
The e-beam lithography apparatus drawing the patterns directly does not need the masks and has higher resolution than the projection type exposure such as a stepper, but it also has an disadvantage of application to a mass-production processing. Therefore, until now, the stepper, one of the reduced projection type exposure apparatus using optical system, has been used in many mass-production processing lines. But, for using the projection type exposure, there are still many problems needed to be solved such as a technical problems and cost-up problems. The technical problems to be solved are as an errors between the masks as much as the number of the masks, an errors caused by a stacking of the overlapping patterns, and an errors caused by the alignment of the masks and also the cost-up problems are a fabrication and control of the expensive masks for each processing steps.